lock, latch, bar, bolt
扂 centers on a physical fastening device for a door or gate: a lock, latch, bar, or bolt that secures an opening.
扂 combines 户 (door) with 占, which likely contributes a phonetic element. The character represents a door fastening, consistent with the door component.
The door enclosure 户 holds a divination shell 占 inside. Imagine using a shell as a makeshift latch to bar the door shut.
For テン, picture ten locks on a single door: ten -> テン, and each lock is a bar or bolt securing the entrance.